What is a Plant Growth Regulator? Is it Harmful to Human Body?
Plant growth regulators are a group of substances which have similar physical and biological effects compared with plant hormones. At present, substances which are able to regulate plant growth and development have been found, including auxin, gibberellic acid (GA), ethephon, cytokinin, S-ABA (abscisic acid), brassinolide (brassinosteroid), salicylic acid, jasmonic acid and polyamines, etc., of which, the first six categories as plant growth regulators are mainly applied to vegetable production. Plant growth regulators have little effect on human, so they can be applied to vegetable production.
a. Plant Growth Regulators and animal hormones are completely different.
Plant growth regulators and animal hormones are completely different, and there is not a common physiological effect between them yet. Plant growth regulators only have effects on plants, but not animals. Most plant growth regulators are relatively simple hydrocarbons such as ethephon, etc., while most animal hormones are amino acids, proteins and their derivatives and steroids. Plant growth regulators and animal hormones are different in components so that their roles are different. Animal hormones have a great impact on human body, while plant growth regulators have no effect on human body but have an obvious effect on plants. Animal hormones, such as thyroid hormone and insulin, etc., have no effect on vegetables, similarly, plant growth regulators, such as gibberellic acid (GA) and brassinolide, etc., have no effect on human body.
b. Hormone is widespread.
In the absence of synthetic plant growth regulators, plant growth regulators in the foods are also indispensable, so it is completely safe to eat. For example, there are more auxin and gibberellic acid (GA) in leaves, buds and fruits of young vegetables, while more ethylene, abscisic acid and other plant growth regulators in ripe fruits. As for bean sprouts and mushrooms recognized as healthy vegetables, they contain a lot of plant growth regulators such as auxin, etc.
c. Plant growth regulators are characteristic of low toxicity, low use concentration and long intervals.
Plant growth regulators are much less toxic compared with insecticides and fungicides, etc. Among chemicals used on vegetables, the greatest harm to human body is insecticides; fungicides come second; hormones are least. Plant growth regulators and other pesticides vary greatly in the toxicity. Plant growth regulators are used at very low concentrations, usually in a few parts per million to dozens of parts per million. For example, brassinolide is used at a low concentration, even only a few parts per hundred million to a few parts per tens million. In addition to ethephon, plant growth regulators are mostly used in the prometaphase of vegetable’s growth, because a longer interval from vegetable harvest can ensure safety. For cucumbers, its harvest time from flowering to harvest is the shortest, with the interval of 7 days or more as well; for tomatoes, the interval of spraying flowers is about two months; mepiquat and MET used in the seedling stage have longer intervals. Although plant growth regulators are basically harmless to human, it still needs to pay attention to control dosage. Plant growth regulators are completely usable according to national pollution-free vegetable production standards.